Throughout the history of the vehicular transportation three principle types of power have been used in conventional vehicles—namely, petroleum (gasoline and diesel) or internal combustion, steam and electric. Further developments in new solid fuel technologies, including hydrogen and alcohol cell devices, and atomic powered vehicles have been attempted. However, the primary drive system for most vehicles has been the internal combustion engine using petroleum fuels.
While the gasoline engine has been the primary power source for vehicles for many years, the energy problems being encountered throughout the world and the environmental impact of emissions from petroleum based fuels have caused an increased interest in various alternative energy sources. Governmental initiatives and commercial demand have, in recent years, increased development efforts of electric energy, zero emission motors as a prime mover for vehicles. Several of these efforts have been based on special applications in the golf course, security, commercial manufacturing, and mass transportation industries where several zero emission vehicles are designed and manufactured for minimal impact on indoor and outdoor environments or for added stealth over conventional gasoline engine vehicles. Additionally, several metropolitan mass transportation systems have utilized electrically powered vehicles in an experimental capacity and automakers continue to pursue both electric and hybrid electric passenger vehicle designs.
Such developments have produced stronger, longer ranged, more efficient, lighter weight vehicles using new materials and improved, long-life, rechargeable batteries substantially extending vehicle operating ranges. These objectives are recognized as essential goals to improve upon in order to achieve wider consumer acceptance of electric powered vehicles. However, one of the, if not the most, important principal aspects to improving the viability of electric powered vehicles is increasing the range of the vehicle or reducing the number of power cells required for operation or both. This would make the vehicle more cost effective to produce and operate as both a passenger vehicle and as a specialty vehicle in specialized roles like surveillance or zero emission mass transportation.
Prior attempts at providing vehicles, especially electrically powered vehicles, with these beneficial characteristics have been made. Several of these efforts have been directed to provide energy recovery systems to golf carts or small vehicles that utilize energy recovery devices. Still further attempts have been directed to utilizing flywheels to store energy from movement in a vehicle or a motor. However, none of these efforts have had any commercial success.
One example of an attempt to provide an energy recovery drive in a golf cart is the device seen in U.S. Pat. No. 3,530,356 to Aronson. The patent discloses a multiple position setting for control of a golf cart. The vehicle engages an alternator and returns energy to a battery bank when a specific pedal condition occurs. The alternator can only be engaged when the vehicle reaches speed and the pedal control is released. The drive mechanism cannot return energy when the vehicle is stationary, nor can it recover energy while accelerating. It runs the alternator only when decelerating and then only from the drive train. Additionally, it does not even suggest the use of a flywheel to recover energy. It simply runs an alternator intermittently from the drive train after a particular control input is released. It is ineffective at returning energy to the batter bank.
U.S. Pat. No. 4,477,764 to Pollard shows an electric vehicle adapted to generate and recharge its principal energy storage devices. The electric motor is driven by depressing an accelerator switch. A speed switch and a gravity switch are also provided, so that during periods of high speed or increased speed going downhill, a generator is engaged to recover energy from the excess speed. Additionally, an “accessories” battery is also charged by an alternator when the drive train is in motion. Again, the principal alternator is only operating when the vehicle is in motion. This requires the vehicle to use additional energy from its batteries to achieve locomotion and, then and only then, can it begin to recover a scintilla of spent energy. This is a significant problem in various vehicular applications. For instance, in the golf industry, the consistent stopping and starting of the vehicle renders this improvement useless as the vehicle never achieves sufficient forward motivation to engage its energy recovery mechanism. Moreover, the device does not return energy when the vehicle is stopped, either before or after it has reached speed. Nor does it utilize a flywheel or infinitely variable transmission unit, such as a traction drive unit.
U.S. Pat. No. 5,686,818 to Scaduto is another attempt directed to a vehicle with a recuperative drive having generators mounted on the axle and a switching mechanism to engage the generators after vehicular motion has begun. The rear wheels are on a shaft and drive a set of alternator/generator combinations. The vehicle begins operation by draining power from the batteries to achieve motion and, at a specified operating condition, the switch activates the alternation/generation of electrical energy, which is returned to the power storage device. Again, the recuperative mechanism of the vehicle relies on utilizing energy to achieve speed and then and only then does it begin returning some of the spent energy. Further, the device does not use a weighted drive member or a traction drive unit. Again, this solution is not suitable for a vehicular application and has not achieved any marked commercial success.
U.S. Pat. No. 4,095,665 to Armfield describes an electric car. The car has a standard gearbox connected through a first clutch to a motor and through a second clutch to a generator. This allows the car to disengage its drive system from the motor and engage the generator by activating and deactivating the clutches. Although the generator can be driven by the drive train, it can only be done while the gearbox is moving. Thus the vehicle cannot recover energy when the vehicle is or becomes stationary. Moreover, the vehicle does not utilize a weighted drive member in its transmission, relying instead on a commonly geared transmission. Nor does it suggest the use of a traction drive unit. The gearbox and generator combination depicted is an inefficient way of trying to recover the kinetic energy of the vehicle given typical acceleration and deceleration patterns in vehicles.
Additionally, several patents have been directed to implementing flywheel devices in vehicle and vehicle drive trains in an attempt to store energy. However, none have been commercially successful and none contemplate using the flywheel as the primary transmission. Further, none of the prior patents have used an energy recovery device in conjunction with the flywheel, but instead typically use the flywheel as the power storage device. Moreover, none have incorporated the flywheel as the principal drive means, instead in keeping with the flywheel as an energy storage device, they shunt power through the flywheel by disconnecting the normal power transmission path.
For instance, U.S. Pat. No. 1,335,249 to Leymarie; U.S. Pat. No. 2,803,151 to Clerk; U.S. Pat. No 2,935,899 to Nallinger; U.S. Pat. No 3,396,607 to Ross; U.S. Pat. No 3,665,788 to Nyman; U.S. Pat. No 3,749,194 to Bardwick, III; U.S. Pat. No 3,672,244 to Nasvytis; U.S. Pat. No 3,771,311 to Herbst; U.S. Pat. No. 4,233,858 to Rowlett; U.S. Pat. No. 4,343,371 to Smitley; and U.S. Pat. No 4,779,485 to Dollison et al. disclose drive units that rotate a flywheel for conservation of energy. However, in these examples and in others like them, the unit charges the flywheel using a pinion gear or similar gear and then utilizes the spinning flywheel to drive the vehicle through a separate transaxle or similar system in conjunction with the primary motor or instead of the primary motor. These designs do not impart energy back to an energy storage device or utilize the flywheel in an efficient manner as part of there transmission, but instead attach it as a power storage device to be utilized for motivation of the vehicle with or in the absence of power from the prime mover. The result is a very inefficient system.
Further examples include U.S. Pat. No. 4,031,421 to Carini, showing a flywheel transmission using geared pinions and driven by multiple electric motors. Again, the pancake drive system shown takes power from a prime mover, in this case the electric motors, to begin turning. The prime movers charge both flywheels. These in turn impart energy to a driven wheel mounted on an axle. This drive unit is more efficient than the pinion gears discussed above. However, no mention of energy recovery from the flywheels is made and the operation of the prime movers is utilized only to motivate the flywheels and then keep them at a specified RPM range. Moreover, no mention is made of recovering energy from the system.
U.S. Pat. No. 4,131,171 to Keyes discloses a low energy consumption vehicle propelled by a thermal engine and using a flywheel. The flywheel is coupled to an infinitely variable ratio transmission. The system is designed to balance energy in a vehicle with a low power thermal engine that is run at a constant energy output. The engine charges the flywheel when the system is not at “peak” power requirements, for instance during idling and coasting periods. Thus this patent is directed to a further modification of the energy storage type designs discussed above. It does not recover energy during deceleration nor does it provide for energy recovery when the motor is de-energized. Instead it simply shifts the energy to a flywheel for storage
In U.S. Pat. No. 4,329,889 to Hachiya provides for a power transmission system for use with and internal combustion engine. The system spins a flywheel and a series of pinioned gears connected to rotational discs that are attached to magnetic clutches. Each of these discs is engaged by the electromagnetic clutch as part of the transmission of the vehicle. These in turn drive a set of gears. The system uses the gearing and disc setup to charge the flywheel when the engine idles and then employs the energy to propel the vehicle. Again, similar to the other patents described above, the flywheel is being used to store energy, not return energy or recover energy from the transmission. The limited recovery of energy from the idling of the engine compared to the added weight of the disks and clutches makes this very inefficient and impractical for use in any vehicle.
In addition, a variety of vehicles have used traction drives, but they have not used the traction drive in conjunction with a flywheel and an energy recovery device to return energy. For instance, U.S. Pat. No. 5,425,684 to Dourgherty; U.S. Pat. No 5,353,578 to Irby et. al.; U.S. Pat. No 4,498,553 to Rouse; U.S. Pat. No. 3,667,304 to Puffer et al.; U.S. Pat. No 3,631,730 to Hadler et al.; U.S. Pat. No 3,613,814 to Prier Jr.; U.S. Pat. No 3,445,991 to Hansen et al.; and U.S. Pat. No 3,327,546 to Gordon et al. all describe various traction drive transmissions for lawn mowers and small vehicles.
The '552 patent to Rouse is an example of the typical use of these drive units. The '552 patent shows a traction drive unit for an internal combustion engine (ICE) on a lawn mower having a driven disc and a traction disc that are intermittently engaged to propel the vehicle. The driven disc, coupled to the motor, is stationary and the traction disc is slid across the driven disc. However, there is no mention of energy or momentum energy recovery. Moreover, the driven disc is not a weighted disc but is only intended to spin to provide contact with the traction disc. There is no mention or consideration in any of this line of patents even entertaining the idea of adding or weighting the elements of the traction drives to spin for prolonged periods of time after the power to the engine is shut off. Nor is there any mention of the use of an energy recovery devices in conjunction with the traction drive units to return energy back to an power storage device, especially an electric power storage device.
Traction drives are also used in other technology areas. For instance, in U.S. Pat. No. 3,022,383 to Springer, a rotatable electromagnetic transducer system for tape drives is shown. Although the transmission of motive forces is through friction plates contacting friction rollers, the invention is directed to solve tape synching problems. However, the system is used to maintain speeds in the playback heads of a recording device. In this instance, the friction plates are not wound at sufficiently high enough revolutions per minute (RPM) to even consider driving a vehicle, much less recovering energy from the drive system.
Additionally, alternators are used in standard automobile starter systems and electrical systems. These systems are used with ICE systems and require “cranking” a starter motor to initiate the ICE system and start the return of energy to battery through the alternator. Although the auxiliary electrical system, typically a 12-Volt battery, remains charged from the alternator, it is used only for starting the vehicle. There is no recuperation of energy from a flywheel for storage, nor is there any suggestion to modify these systems to do so.
To date, no device has achieved a substantial return of energy to a storage device in for a sufficient duration of time, including while idling, to extend the operating range of a vehicle. Additionally, those proposals that have been attempted add unreasonable costs to the vehicle. Therefore, a continued need exists for an improved energy recovery system for use in vehicles, especially for use in vehicles employing electrical drive units, that is cost effective and operates to extend range and reduce weight. A need also still exists for a recuperative drive mechanism that drives a vehicle and can achieve a return of energy while moving, while coasting, and even while sitting still. The improved efficiency of such a device would allow for longer duration of operation in vehicles, especially electric vehicles. Similarly, in the case of electric vehicles, such a device would allow for additional electrical accessories heretofore unusable if such an electric vehicle while maintaining a reasonable duration of operation. Ultimately, such a device could be utilized in developing zero emission passenger vehicles and other commercial vehicles for everyday use for day to day driving.